A typical voltage stabilizer is able to respond to voltage fluctuations called voltage drops (low voltage) and voltage increases (high voltage) in the input line from the network. The declines can be the result of irregular distribution of voltage in the consumer network, connections of large loads in the network, inefficient grounding, etc.

Rises can arise from the immediate disconnection of large loads from the network, high voltage produced by HPP, TEC, etc., atmospheric causes, etc. The duration and frequency of these phenomena depends on the cause and is not easy to predict.

Voltage drops are usually more frequent, especially where the distribution is not controlled.

Other disturbances such as hums, high frequencies, noises and distortions of harmonics can be filtered through special filtering systems. The regular operation of most electrical and electronic equipment depends on the accuracy and stability of the input voltage. Nowadays, many private or state consumers are subject to long-term voltage fluctuations that can be accompanied by unpleasant effects or even serious damage.